[llvm-readobj] Add support for MachO DataInCodeDataCommand

[davide]

Summary

macho-dump has this. And some tests rely on it.
I ported it to llvm-readobj as part of the bigger project "let's deprecate macho-dump".
Example output:

% /exps/llvm2/build/./bin/llvm-mc -triple armv7-apple-darwin10 -filetype=obj -o - < /exps/llvm2/test/MC/MachO/ARM/data-in-code.s | /exps/llvm2/build/bin/llvm-readobj -macho-dice

File: <stdin>
Format: Mach-O arm
Arch: arm
AddressSize: 32bit
DataInCode {

Data offset: 300
Data size: 32
Data Regions [
  DICE {
    Index: 0
    Offset: 0
    Length: 4
    Kind: 1
  }
  DICE {
    Index: 1
    Offset: 4
    Length: 4
    Kind: 4
  }
  DICE {
    Index: 2
    Offset: 8
    Length: 2
    Kind: 3
  }
  DICE {
    Index: 3
    Offset: 10
    Length: 1
    Kind: 2
  }
]

}

Feedback really appreciated.

[davide]

+ Kevin, who's not on phab.

[• rafael]

LGTM with nits since this will be getting tests as it replaces macho-dump.

MachODumper.cpp

614

Regions or entries?

619

Entry (or Region) is probably better than DICE.

llvm-readobj.cpp

186

Name the option macho-data-in-code maybe?

[davide]

Thank you for reviewing, Rafael. I agree with -macho-data-in-code. About the difference between region/entries -- I don't have strong preferences, so I'll change as you say (I just blatantly copied what was used in macho-dump). Maybe grosbach or enderby have a different opinion.

[llvm-commits]

I went forward and commited this as r245732.
If anybody has other opinions about the lexicon -- we can change it later.
I'll start converting macho-dump tests soon so this feature will get tested.

Thanks,

Davide

MachODumper.cpp

public:
   void printFileHeaders() override;
   void printSections() override;
   void printRelocations() override;
   void printSymbols() override;
   void printDynamicSymbols() override;
   void printUnwindInfo() override;
   void printStackMap() const override;
 
+  // MachO-specific.
+  void printMachODataInCode() override;
+
 private:
   template<class MachHeader>
   void printFileHeaders(const MachHeader &Header);
 
   void printSymbol(const SymbolRef &Symbol);
 
   void printRelocation(const RelocationRef &Reloc);
 
void MachODumper::printStackMap() const {
   if (Obj->isLittleEndian())
      prettyPrintStackMap(
                       llvm::outs(),
                       StackMapV1Parser<support::little>(StackMapContentsArray));
   else
      prettyPrintStackMap(llvm::outs(),
                          StackMapV1Parser<support::big>(StackMapContentsArray));
 }
+
+void MachODumper::printMachODataInCode() {
+  for (const auto &Load : Obj->load_commands()) {
+    if (Load.C.cmd  == MachO::LC_DATA_IN_CODE) {
+      MachO::linkedit_data_command LLC = Obj->getLinkeditDataLoadCommand(Load);
+      DictScope Group(W, "DataInCode");
+      W.printNumber("Data offset", LLC.dataoff);
+      W.printNumber("Data size", LLC.datasize);
+      ListScope D(W, "Data Regions");
+      unsigned NumRegions = LLC.datasize / sizeof(MachO::data_in_code_entry);
+      for (unsigned i = 0; i < NumRegions; ++i) {
+        MachO::data_in_code_entry DICE = Obj->getDataInCodeTableEntry(
+                                                              LLC.dataoff, i);
+        DictScope Group(W, "DICE");
+        W.printNumber("Index", i);
+        W.printNumber("Offset", DICE.offset);
+        W.printNumber("Length", DICE.length);
+        W.printNumber("Kind", DICE.kind);
+      }
+    }
+  }
+}

ObjDumper.h

public:
   virtual void printMipsReginfo() { }
 
   // Only implemented for PE/COFF.
   virtual void printCOFFImports() { }
   virtual void printCOFFExports() { }
   virtual void printCOFFDirectives() { }
   virtual void printCOFFBaseReloc() { }
 
+  // Only implemented for MachO.
+  virtual void printMachODataInCode() { }
+
   virtual void printStackMap() const = 0;
 
 protected:
   StreamWriter& W;
 };
 
 std::error_code createCOFFDumper(const object::ObjectFile *Obj,
                                  StreamWriter &Writer,

llvm-readobj.cpp

namespace opts {
   COFFDirectives("coff-directives",
                  cl::desc("Display the PE/COFF .drectve section"));
 
   // -coff-basereloc
   cl::opt<bool>
   COFFBaseRelocs("coff-basereloc",
                  cl::desc("Display the PE/COFF .reloc section"));
 
+  // -macho-dice
+  cl::opt<bool>
+  MachODataInCode("macho-dice",
+                  cl::desc("Display MachO Data in Code command"));
+
   // -stackmap
   cl::opt<bool>
   PrintStackMap("stackmap",
                 cl::desc("Display contents of stackmap section"));
 
 } // namespace opts
 
 namespace llvm {
if (opts::COFFImports)
       Dumper->printCOFFImports();
     if (opts::COFFExports)
       Dumper->printCOFFExports();
     if (opts::COFFDirectives)
       Dumper->printCOFFDirectives();
     if (opts::COFFBaseRelocs)
       Dumper->printCOFFBaseReloc();
   }
+  if (Obj->isMachO())
+    if (opts::MachODataInCode)
+      Dumper->printMachODataInCode();
   if (opts::PrintStackMap)
     Dumper->printStackMap();
 }
 
 /// @brief Dumps each object file in \a Arc;
 static void dumpArchive(const Archive *Arc) {
   for (const auto &Child : Arc->children()) {
     ErrorOr<std::unique_ptr<Binary>> ChildOrErr = Child.getAsBinary();